1. Field of the Invention
This invention pertains to components for use with stringed instruments and relates in particular to frets which are inserted in the instrument neck.
2. Description of the Prior Art
Stringed instruments typically include a neck over which the strings extend. The strings are plucked to provide tones and tone changes are achieved by varying string length. Frets are inserted in the neck at pre-determined locations beneath the strings and string length is adjusted by pressing the string into contact with a specific fret.
Conventionally, the frets are made of a metal such as nickel silver and have a somewhat T-shaped configuration wherein the stem of the T is inserted in the instrument neck and the cap provides a bearing surface for the strings. The spacing of the frets is such that the central axis passing longitudinally through the long axis of the stem is located at a point which, in reference to the fixed end of the strings, defines a distance such that a string of length equivalent to that distance will provide a tone of precise frequency when the string is plucked.
Heretofore, the cap of the fret has had a convex shape. That is, it bulges upwardly away from the stem. Thus, when the frets are in place on the neck, they present a series of parallel ridges all having a rounded surface projecting upwardly towards the strings.
While the spacing of the frets with respect to each other can readily be maintained with precision, the height of the caps above the neck surface often varies. Such height variations must be eliminated, however, so that all of the strings will be properly spaced above the fret surface. The spacing between the strings and the frets must be properly established so as to produce proper tonal qualities. Consequently, it is custumary to grind the raised surfaces of the fret caps until all are coincident with a common plane lying parallel to the neck surface.
While grinding in the described manner readily produces the desired constancy of fret height, tone variations are nevertheless often experienced when the instrument is played.
Accordingly, one object of this invention is to achieve proper spacing between the fret tops and the strings without impairing tonal accuracy when the instrument is played.
In analyzing conventional frets, it has been discovered that the flats caused by grinding become so large that the point of contact between string and fret shifts away from the central axis of the fret when contact is made. As a result, the actual string length fails to coincide with the designed string length and an inaccuracy of tone results when the string is plucked. It is important, therefore, that the actual string length approach coincidence with the designed string length in order to produce instruments of quality. The movements towards coincidence, however, must not adversely affect the instrument's playing characteristics.
Accordingly, another object of this invention is to achieve a closer approach to coincidence between designed string length and the actual string length which occurs when a string is pressed against a fret and to achieve that closer approach without changing the playing characteristics of the instrument.